I actually had to develop a vBulletin modification for a potential partner. Since MMOG runs vBulletin it made good sense to test it here - and it's a good integration point for the sister sites.
Besides, the postbit link properly handles the SEO'd links we have and each "page" is a separate link - unlike the crappy social bookmarking link vB has by default.
Watch this space - /gg FTW has some huge potential and we have some strong partners considering working with us - I'm excited about the future of this project!